Parking brakes of many different kinds have long been used on a wide variety of vehicles, including on, among others, a wide variety of work vehicles. One example of prior devices is disclosed in U.S. Pat. No. 5,551,523 and is usable in a skid-steer loader. In some cases it is desirable that parking brakes not be engageable at vehicle speeds above some predetermined level--that is, that the braking effect they provide only be available in a predetermined speed range of zero up to the predetermined level. This range is referred to herein as the "engagement-speed range." If a parking brake system, like some, is unable to prevent parking brake engagement when the vehicle is moving at high speeds, brake engagement at such high speeds can cause major component failures because components of the parking brake are unable to absorb the high levels of kinetic energy that high speeds involve. The result can be breakage of brake parts and the consequent need for repairs.
There is a clear need for improvement in parking brake devices which cannot be engaged at speeds above a predetermined level--i.e., which can only be engaged at or below a given speed. There is a need for improved vehicle parking brake systems which are rendered unable to engage at high speeds--i.e., beyond those for which parking brake engagement is desirable. Parking brake systems, particularly systems with advanced capabilities, can tend to be complicated and, therefore, expensive. There is a need for an improved parking brake which is simple and economical in construction but still has the capability of being unable to fully engage at high speeds.